Disk drives are information storage devices that use thin film magnetic media to store data. A typical disk drive includes one or more rotating disk having concentric data tracks wherein data is read or written. As the disk rotates, a transducer (or xe2x80x9cheadxe2x80x9d) is positioned by an actuator to magnetically read data from or write data to the various tracks on the disk. When the disk is rotating at operating speeds, pressure effects caused by air flow between the surface of the disk and an air bearing surface of the head cause the head to float above the disk. Once a predetermined rotational speed and head fly height (i.e. float height) is reached, reading and/or writing of data may commence. Maintaining proper fly height is essential to the accurate and reliable operation of the disk drive.
A disk head loading force adjustment mechanism that can be used to dynamically shift a load point of a disk head. Shifting the load point can alter the pitch of the disk head and, consequently, the fly height of the head. This allows for active head fly height control and can provide advantages such as better mechanical integrity of a magnetic hard disk drive. A drive may be constructed such that the head flies higher in the landing zone and flies lower in the data zone. This can help minimize magnetic spacing loss in a disk""s data zone and may permit higher areal densities to be achieved. In addition, the active control of the load point can help reduce head fly height differences between different heads in a drive or in different drives, thereby providing for more consisting head operation across manufactured drives.
In general, in one aspect, the invention features a disk head fly height adjustment method. The method includes positioning a disk head over a surface of a rotating data storage disk and dynamically altering a load point of the disk head by changing an electrical force applied to an active element mounted to a gimbal assembly.
In general, in another aspect, the invention features a data storage apparatus that includes a head assembly having a data transfer head coupled to a gimbal and an active element coupling the head assembly and a suspension. The active element is configured to exert a force between the head assembly and the suspension in response to an electrical force applied to the active element.
Implementations may include one or more of the following features. The invention may be used with disk media having a magnetically alterable surface having a data zone and a landing zone. Other disk media types also may be used. Positioning control circuitry may change the fly height of an air bearing disk head depending on whether the disk head is positioned over the landing zone or the data zone. The loading force may be dynamically altered in response to a signal from the disk head, such as a data read strength signal. Changing the loading force may be done by changing an electrical force (such as a current or a voltage) applied to an active element mounted to, or formed as part of, a head-gimbal assembly. Altering the load point may alter a pitch angle of the disk head. The active element may be a solenoid that may have a core coupled to the gimbal assembly and a magnetically active element coupled to the suspension. Other active elements, such as piezo-electric elements, also may be used. Apparatus embodying the invention also may include a disk coupled to a disk rotating motor and an actuator coupled to a suspension and configured to position the head assembly over a surface of the disk media.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.